1. Field of the Invention
Aspects of the present invention relate to a method for estimating location and an apparatus using the same, and more particularly, to a method for estimating location using an external device, and an apparatus using the same.
2. Description of the Related Art
Mobile communication terminals such as mobile phones have become widely used. With the remarkable development of the function and efficiency of mobile communication terminals, the mobile communication terminals have various functions for transmitting and receiving e-mail, and for providing location information, in addition to basic communication functions.
There are various methods of providing information regarding the location of a terminal in a mobile communication system. First, there is a method for providing location information in which the distance between a terminal and a satellite is estimated by measuring the phase of a carrier wave signal transmitted from a Global Positioning System (GPS) satellite, or by estimating codes of a carrier wave signal. However, it is difficult to receive a GPS signal if there are obstacles intervening between the terminal and the GPS satellite, for example in a densely built-up area or indoors.
Second, there is a method of providing location information in which the distance between a mobile terminal and a base station is estimated using a time delay between signals transmitted from a plurality of base stations. However, the above method may provide inaccurate location information, since errors occur depending on the radius of a cell of a base station, with an error tolerance ranging from 500 m to many km.
Third, there is a wireless communication method for providing location information in which the location is recognized using a Diffuse infrared, ultrasonic, the radio frequency (RF), ultra wideband (UWB), and radio frequency identification (RFID) beacon. The method is appropriate for determining an indoor location, but a plurality of auxiliary devices are required. Thus, there is a need for a method of providing more efficient and accurate location information within an area in which it is not possible to receive a GPS signal or in which the GPS service is unavailable.